In general, it is known that in an electronic camera, color misregistration occurs on a captured image due to magnification chromatic aberration of an imaging optical system. Some technologies for correcting such color misregistration by image processing have been proposed up to now.
For example, in Patent Document 1, when lost color components of raw data are produced by color interpolation, magnification chromatic aberration is corrected at the same time by manipulating an interpolation coefficient.
Furthermore, for example, in Patent Document 2, a method of compensating for sharpness lost by correction of color misregistration is disclosed. In this method, interpolation coefficient data which represent the amounts of misregistration of correction object color components (e.g. R and B components) are obtained first. Next, a complementary coefficient of the interpolation coefficient data is obtained, and reference color components (e.g. G components) are multiplied by the complementary coefficient. The result of the multiplication is added to the correction object color components to compensate for the sharpness lost.
Furthermore, for example, in Patent Document 3, a method of producing color misregistration corrected color difference components (R-G) and (B-G) by scaling the G components of raw data in accordance with the magnification chromatic aberration of the R and B components and subtracting the scaled G components from the R and B components is disclosed. In this method, a suitable correction is made particularly in an achromatic image area.
In this specification, “raw data” correspond to “image data having one kind of color components per pixel” in the Claims.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2001-186533 (Paragraph 0043)
Patent Document 2: Japanese Patent Publication No. 2552742
Patent Document 3: Japanese Unexamined Patent Application Publication No. 2002-112276